Uphill Welding the Root Bead on Heavy-Wall Pipe (5G Position)

The Root Bead

The root bead is the foundation of a successful pipe weld and must be made as perfectly as possible. An illustration of a perfect root bead is shown in Fig. 5- І.

Uphill Welding the Root Bead on Heavy-Wall Pipe (5G Position)

Fig. 5-1. A. Top view of a perfect root bead; B. View of section through the root

bead.

Perhaps the most difficult position in which to weld pipe is in the horizontal, or 5G, position. Once this is mastered, welding pipe in other positions is less difficult to learn. For this reason, it is best to start by learning how to weld in the 5G position.

For practice welding in the 5G position, a convenient method of holding the pipes is to clamp them in a fixture or pipe stand as shown in Fig, 5-2A. Two previously tack welded pipe nipples are shown clamped in position on the pipe stand in Fig. 5-2B. When clamping the pipe nippies in the fixture, they should be positioned so that the tack welds are in the positions shown in Fig. 5-2C.

Uphill Welding the Root Bead on Heavy-Wall Pipe (5G Position)

Uphill Welding the Root Bead on Heavy-Wall Pipe (5G Position)

Courtesy of the Hobart Bnnhers Co. Fig. 5-2. Pipe welding stand. A. Unloaded stand; B. Pipe clamped in place; C, Position of tack welds.

Figure 5-3 gives a view of the details of the pipe stand. While all of the details are shown, not all of the dimensions are given because they depend on the size of the pipe to be welded and must be specified accordingly. From this illustration it should be possible to design a pipe stand on which the practice welds can be made.

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